按键控制led驱动

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>
#include <mach/gpio-fns.h>

#include <linux/poll.h>

#include <asm/irq.h>

#include <linux/interrupt.h>
#include <linux/irq.h>
#include <asm/irq.h>

#include <linux/sched.h>

#include <linux/device.h>   	//class_create()函数头文件

#define DEVICE_NAME    "buttons" //设备名称
#define DEVICE_MAJOR   289              //主设备号

#define KEY_DOWN            0   //按键按下
#define KEY_UP              1   //按键抬起
#define KEY_UNCERTAIN       2   //按键不确定
#define KEY_COUNT           6   //6个按键

#define KEY_TIMER_DELAY1  (HZ/50)       //按键按下去抖延时20毫秒
#define KEY_TIMER_DELAY2  (HZ/10)       //按键抬起去抖延时100毫秒

#define IOCTL_LED_ON 		0
#define IOCTL_LED_OFF 		1
#define IOCTL_LED_ALL_ON 	2
#define IOCTL_LED_ALL_OFF 	3

static volatile int ev_press = 0;      //按键按下产生标识，用于在读设备的时候来判断是否有数据可读，否则进程睡眠

static DECLARE_WAIT_QUEUE_HEAD(button_waitq); //等待队列的定义并初始化
static unsigned long led_table [] =
{
S3C2410_GPB5,
S3C2410_GPB6,
S3C2410_GPB7,
S3C2410_GPB8,
};
static unsigned int led_cfg_table [] =
{
S3C2410_GPIO_OUTPUT,
S3C2410_GPIO_OUTPUT,
S3C2410_GPIO_OUTPUT,
S3C2410_GPIO_OUTPUT,
};

static volatile int key_status[KEY_COUNT];      //记录6个按键的状态
static struct timer_list key_timers[KEY_COUNT]; //6个按键去抖动定时器
//组织硬件资源结构体
struct button_irq_desc
{
int irq;         //中断号
int pin;         //对应的IO引脚
int pin_setting; //引脚配置
char *name;      //按键名称，注意这个名称，在后面的一个现象中会出现
};

//定义6个按键资源结构体数组
static struct button_irq_desc button_irqs[] =
{
{IRQ_EINT8 , S3C2410_GPG0 , S3C2410_GPG0_EINT8  , "KEY0"},
{IRQ_EINT11, S3C2410_GPG3 , S3C2410_GPG3_EINT11 , "KEY1"},
{IRQ_EINT13, S3C2410_GPG5 , S3C2410_GPG5_EINT13 , "KEY2"},
{IRQ_EINT14, S3C2410_GPG6 , S3C2410_GPG6_EINT14 , "KEY3"},
{IRQ_EINT15, S3C2410_GPG7 , S3C2410_GPG7_EINT15 , "KEY4"},
{IRQ_EINT19, S3C2410_GPG11, S3C2410_GPG11_EINT19, "KEY5"},
};

//驱动程序中的轮询，用于应用程序中的轮询查询是否可对设备进行访问
static int buttons_poll(struct file *file, struct poll_table_struct *wait)
{
unsigned int mask = 0;

//添加等待队列到等待队列表中(poll_table)
poll_wait(file, &button_waitq, wait);

if(ev_press)
{
//标识数据可以获得
mask |= POLLIN | POLLRDNORM;
}

return mask;
}

static irqreturn_t buttons_interrupt(int irq, void *dev_id)
{
//获取当前按键资源的索引
int key = (int)dev_id;
//判断当前按键的状态已经抬起后才服务中断
if(key_status[key] == KEY_UP)
{
//设置当前按键的状态为不确定
key_status[key] = KEY_UNCERTAIN;

//设置当前按键按下去抖定时器的延时并启动定时器
key_timers[key].expires = jiffies + KEY_TIMER_DELAY1;
add_timer(&key_timers[key]);
}
switch(key){
case 1:
printk("led1 on\n");
s3c2410_gpio_setpin(led_table[0], 0);//点亮相应的管脚
s3c2410_gpio_setpin(led_table[1], 0);//点亮相应的管脚
s3c2410_gpio_setpin(led_table[2], 0);//点亮相应的管脚
s3c2410_gpio_setpin(led_table[3], 0);//点亮相应的管脚

return 0;
case 2:
printk("led2 on\n");

s3c2410_gpio_setpin(led_table[0], 1);//熄灭相应的管脚
s3c2410_gpio_setpin(led_table[1], 1);//熄灭相应的管脚
s3c2410_gpio_setpin(led_table[2], 1);//熄灭相应的管脚
s3c2410_gpio_setpin(led_table[3], 1);//熄灭相应的管脚
return 0;
case 3:
printk("led3 on\n");
return 0;
case 4:
printk("led4 on\n");
return 0;
default:
return 0;
}
return IRQ_RETVAL(IRQ_HANDLED);
}

static void buttons_timer(unsigned long arg)
{
//获取当前按键资源的索引
int key = arg;

//获取当前按键引脚上的电平值来判断按键是按下还是抬起
int up = s3c2410_gpio_getpin(button_irqs[key].pin);

if(!up)//低电平，按键按下
{
if(key_status[key] == KEY_UNCERTAIN)
{
//标识当前按键状态为按下
key_status[key] = KEY_DOWN;

//标识当前按键已按下并唤醒等待队列让设备进行读取
ev_press = 1;

wake_up_interruptible(&button_waitq);
}

//设置当前按键抬起去抖定时器的延时并启动定时器
key_timers[key].expires = jiffies + KEY_TIMER_DELAY2;
add_timer(&key_timers[key]);

}
else//高电平，按键抬起
{
//标识当前按键状态为抬起
key_status[key] = KEY_UP;
}
}

static int buttons_close(struct inode *inode, struct file *file)
{
int i;

//释放6个定时器和中断
for(i = 0; i < KEY_COUNT; i++)
{
del_timer(&key_timers[i]);

disable_irq(button_irqs[i].irq);
free_irq(button_irqs[i].irq, (void *)i);
}

return 0;
}
static int buttons_read(struct file *file, char __user *buf, size_t count, loff_t *offp)
{
unsigned long ret;

if(!ev_press)//按键按下发生标识，0没有发生

{
if(file->f_flags & O_NONBLOCK)
{
//应用程序若采用非阻塞方式读取则返回错误
return -EAGAIN;
}
else
{
//以阻塞方式读取且按键没按下产生，让等待队列进入睡眠
wait_event_interruptible(button_waitq, ev_press);
}
}

//1为按键按下产生，并清除标识为0，准备给下一次判断用
ev_press = 0;

//将内核中的按键状态数据拷贝到用户空间给应用程序使用
ret = copy_to_user(buf, (void *)key_status, min(sizeof(key_status), count));

return ret ? -EFAULT : min(sizeof(key_status), count);
}

static int buttons_open(struct inode *inode, struct file *file)
{
int i;
int ret;
for(i = 0; i < KEY_COUNT; i++)
{
//设置6个IO口为中断触发方式
s3c2410_gpio_cfgpin(button_irqs[i].pin, button_irqs[i].pin_setting);

//设置中断下降沿为有效触发
set_irq_type(button_irqs[i].irq, IRQ_TYPE_EDGE_FALLING);

//申请中断(类型为快速中断，中断服务时屏蔽所有外部中断？)
ret = request_irq(button_irqs[i].irq, buttons_interrupt, IRQF_DISABLED, button_irqs[i].name, (void *)i);

if(ret)
{
break;
}

//初始化6个按键的状态为抬起
key_status[i] = KEY_UP;

//初始化并设置6个去抖定时器
setup_timer(&key_timers[i], buttons_timer, i);
}

if(ret)
{
//中断申请失败处理
i--;

for(; i >= 0; i--)
{
//释放已注册成功的中断
disable_irq(button_irqs[i].irq);
free_irq(button_irqs[i].irq, (void *)i);
}

return -EBUSY;
}
for (i = 0; i < sizeof(led_cfg_table)/sizeof(led_cfg_table[0]); i++)
{  //设置LED的GPIO口的输出状态
s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
}

return 0;

}

static struct file_operations buttons_fops =
{
.owner        = THIS_MODULE,
.open         = buttons_open,
.release      = buttons_close,
.read         = buttons_read,
.poll         = buttons_poll,
};

/*自动创键设备节点函数声明，上层应用程序都是通过对设备文件的操作来控制下层硬件*/
static struct class *button_class;

static int __init button_init(void)
{
int ret;

//注册字符设备
ret = register_chrdev(DEVICE_MAJOR, DEVICE_NAME, &buttons_fops);

if(ret < 0)
{
printk(DEVICE_NAME " register faild!\n");
return ret;
}
/* 设备节点文件自动创建的实现*/
button_class = class_create(THIS_MODULE, DEVICE_NAME);/*注册一个类，使mdev可以在"/dev/"目录下面建立设备节点*/
if(IS_ERR(button_class))
{
printk("Err: failed in tope-leds class. /n");
return -1;
}
device_create(button_class, NULL, MKDEV(DEVICE_MAJOR, 0), NULL, DEVICE_NAME);//创建一个设备节点，节点名为DEVICE_NAME
printk(DEVICE_NAME " initialized/n");//打印信息，内核中的打印用printk函数

return 0;
}

static void __exit button_exit(void)
{
//注销字符设备
unregister_chrdev(DEVICE_MAJOR, DEVICE_NAME);
device_destroy(button_class, MKDEV(DEVICE_MAJOR, 0)); //删掉设备节点
class_destroy(button_class);     //注销类

}

module_init(button_init);
module_exit(button_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("My2440 button driver");

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(int argc, char **argv)
{
int fd;
int key_status[6];

//以阻塞方式打开设备文件，非阻塞时flags=O_NONBLOCK
fd = open("/dev/buttons", 0);

if(fd < 0)
{
printf("Open Buttons Device Faild!\n");
exit(1);
}

while(1)
{
int i;
int ret;
fd_set rds;

FD_ZERO(&rds);
FD_SET(fd, &rds);

//应用程序进行轮询，查询是否可对设备进行访问
ret = select(fd + 1, &rds, NULL, NULL, NULL);

if(ret < 0)
{
printf("Read Buttons Device Faild!\n");
exit(1);
}

if(ret == 0)
{
printf("Read Buttons Device Timeout!\n");
}
else if(FD_ISSET(fd, &rds))
{
//读设备
ret = read(fd, key_status, sizeof(key_status));

if(ret != sizeof(key_status))
{
if(errno != EAGAIN)
{
printf("Read Button Device Faild!\n");
}

continue;
}
else
{
for(i = 0; i < 6; i++)
{
//对应驱动中按键的状态，为0即按键被按下
if(key_status[i] == 0)
{
printf("Key%d DOWN\n", i + 1);
}
}
}
}
}

close(fd);

return 0;
}

obj-m :=aaa.o
KDIR := /linux-2.6.33.3
PWD := $(shell pwd)
ARCH = arm
CROSS_COMPILE = arm-linux-
default:
$(MAKE) ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) -C $(KDIR) M=$(PWD) modules
clean:
rm -rf .*.cmd *.o *.mod.c *.ko .tmp_versions *.order *symvers *Module.markers